I made my payments in 2 tranches Feb, this year and then on March 25th, a couple of weeks before the deadline. Checked the gateway last week and it's all uploaded, back to 2006. Didn't phone or write, just put Class 2 contributions in one of the comments boxes on the bank transfer.
My wife did the same and her record is not updated yet. I've sent a letter, for her this week, to allocate the payment.
I'm not sure there is any consistency in when they update these records. I suppose, unless you're retiring this year, it doesn't matter too much.